A magnetic disk unit comprises a rotary disk having concentric data tracks storing information, a head reading data from or writing data tracks, and an actuator moving the head to the desired track and connected to a head carrier to keep the head in the center of the track during reading or writing. Therefore, in many disk units, an air-bearing slider has mainly been used as a head carrier. This air-bearing method uses air between a disk and head, and makes the head run on the disk by floating the head a predetermined distance from the disk surface.
However, among recent magnetic disk units requiting higher recording and playback density, new units have appeared that reduce the gap between the magnetic disk and magnetic head and get higher recording density with a reduced recording and reading radius. One example of them is a head contact method in which the head records and plays back almost in contact between the head and disk, allowing the head to read and write with a narrower gap between the disk than in the prior air-bearing method. Using this structure, it is possible to attain higher recording density than with a floating head using the prior air-bearing method.
However, this contact magnetic disk unit poses the possibility of disk or head damage by contact friction between the magnetic disk and head. A structure is proposed to avoid this damage, supplying adequate lubricant to the disk and keeping the lubricant between the disk and head. A ski liquid contact is also proposed, forming sliding legs being comprised of convex parts, and contacting these legs to the lubricant film on the magnetic disk surface to make the head slide on the disk with less friction. However, these methods require various tasks, such as lubricant volume adjustment and replacing lubricant.
One lubricant supply type for a magnetic disk recently proposed is a lubricant circulation type which draws the lubricant supplied to a disk surface from a supply assembly, and supplies it to the disk surface from the supply assembly. However, these withdrawal types require a bigger scale for the whole unit, going against trends in downsizing.
Furthermore, problems arise in positioning and space for a lubricant supply source. In the limited space on the magnetic disk unit, it is required to supply lubricant uniformly and stably to the disk surface over a long period.
An example of a previously proposed lubricant supply is one disposing a nozzle tip for lubricant supply to supply the lubricant from an upper position to the predetermined location on the inner circumference of the disk surface, but this has problems in the aspects of uniform lubricant supply and downsizing.